Overload spring



June 28, 1960 F. J. LAHER `ovERLoAD SPRING United States Patent Oiice Patented June 28, 1960 OVERLOAD SPRING Frank J. Laber, 120 Camino Solrante, Orinda, Calif.

Filed oct. 21, 1957, ser. No. 691,276

9 Claims. (Cl. 267-45) This invention relates generally to overload springs and more particularly to overload springs of the type which are detachably mounted on conventional semielliptical leaf springs.

This application is a continuation-impart of application Serial No. 620,32l, tiled November 5, 1956, now abandoned.

1n many instances, it is desirable to supplement the rear springs of a vehicle particularly when an additional load is carried by the rear of the vehicle. This is particularly true when heavy loads are carried within the vehicle itself or when the vehicle is utilized for pulling trailers, boats, and the like. It is well known that many types of trailers place heavy loads on the rear springs of the vehicle and for that reason supplemental or helper springs are required. Such springs, generally called overload springs, may also, be used, when the conventional springs have lost part`of their resiliency and have begun to sag, to raise the frame of the vehicle to the proper relationship with respect to the running gear of the vehicle. Since a vehicle is not always overloaded, it is generally desirable that overload springs be readily a'ttachable and detachable. `In the past, springs of this type have been objectionable on this account, particularly because they have been diilicult to remove because the means of attachment often utilized bolts or the like which have become rusty during use.

In general, it is an lobject of the present invention to provide an overload spring which is quickly attachable to and detachable from the semielliptical spring of the vehicle.

Another object of the invention is to provide an o ver load spring of the above character which may be mounted on the conventional semi-elliptical spring of the vehicle without alternden of the semi-elliptical spring and without disturbing the conventional connections for the semielliptlcal,springs. s Another object of the invention is to provide an over yload spring of the above character in which the clearsnee on the vehicle is not impaired substantially. i

Another object of the invention is to provide an,over load spring of the above character which is silent acting.

,Another object of the invention is to provide an overload spring of the above character which cannot become disconnected accidentally. i v

Another object of the invention is to provide an overload spring of the above character which can be attached and detached by the use of a conventional jack.

Additional features and objects of the invention will appear from the following description in which the preferred embodiments have been set forth in detail in coniuiction'with the accompanying drawing.

Referring to the drawing: v

Figure l is a side elevational view of an overload spring incorporating the present invention and mounted upon a conventional semi-elliptical spring.

yFigure 2 is a cross-sectional view taken along the line Figure 3 is a crosssectional view taken along the line 3*3 of Figure l.

Figure 4 is a cross-sectiona1 view similar to Figure 2 but showing the method of attaching the overload spring to the semi-elliptical spring of the vehicle.

Figure 5 is a cross-sectional view showing another embodiment of my invention.

As shown in the drawing, an overload spring 11 incorporating my invention is secured to a conventional semi-elliptical spring 12 in a manner hereinafter described. The semi-elliptical spring 12 is secured to the frame 13 of a vehicle in a conventional manner. As shown, the front end of the spring is pivotally connected to a bracket 14 secured to the frame 13 whereas the rear end of the spring is pivotally connected to the lower end of a shackle 16 and the upper end of the shackle is pivotally connected to the frame 13. The intermediate portion of the semi-elliptical spring 12 is secured to the axle housing 17 by a U-bolt assembly 18 consisting of spaced U-bolts 19, a saddle block 21 and a plate 22.

As is shown in the drawing, my overload spring is comprised of a plurality of spring leaves 24, 25 and 26 of various lengths.v The leaves are formed in such a manner that they have an arch in an unloaded condition which is substantially greater than the arch of the conventional semi-elliptical spring when the semi-ellip-v tical spring is carrying its normal load.

Particularly novel means is utilized for securing the leaves of the overload spring to the semi-elliptical spring and consists of clamps 27 and 28. As shown, the clamps are substantially C-shaped and are provided with openings 29 whichface in opposite directions for a purpose hereinafter described. Each'of the clamps are identical and consistsof two parts. As shown in Figure 2, clamp 28 consists of an upper part 31 and a lower part 32. The upper pan 31 is comprised of a substantially horizontal portion 31a, a substantially vertical portion 3lb, and a portion 31e which is ared or bent outwardly from the vertical as shown for a purpose hereinafter described. The upper part 31 is also comprised of a portion 31d which is inclined inwardly with respect to portion 31b and is provided with an opening 34 through which a tongue 36 provided on the lower part 32 normally extends as shown in Figure 2. The tongue 36, as will be noted, is inclined downwardly from the horizontal.

The lower part 32 is substantially Ushaped and has its upper leg 32a engaging the upper surface of the upper leaf spring 26 and its lower leg 32b engaging the lower surface of the leaf 24. The lower part 32 is secured to the leaves 24, 25 and 26 by suitable means such as the nut-and bolt assembly 38 shown. It will be noted that the lower parts 32 of the clamps 27 and 28 together with the nut and bolt assemblies 38 serve to bind the leavesv 24, 25 and 26 into a unitary assembly.

A pair of identical brackets 41 and 42 are mounted on opposite ends of the leaf 26. A detail of bracket 41 is shown in Figure 3 and as shown consists of a substantially U-shaped member 43. The intermediate portion of the U-sh'aped member engages the lower surface of the leaf 26 and is secured thereto by suitable means such as the bolt 44 and the nut 45. The upper end outer ends of the U-shaped member are provided with holes 46 which accommodate a keeper bolt 47 on which is threaded a nut 48. A spacing member 49 is mounted on the bolt 47 and serves to keep the upper ends of the U-shaped member out of engagement with the side edges of the semi-elliptical spring to prevent scraping' and rattling noises.

It will be noted that a cushioning member 51 ofsuitable resilient material such as rubber is mounted on the ends of the leaf 26 and normally engages the lower surface of the semi-elliptical spring 12 to prevent the outer ends of thc overload spring from engaging the semielliptical spring. The cushioning members 51 serve to insure silent action of the overload spring and prevent any noises which might occur if the ends of the overload spring came in direct contact with the semiellip tical spring. 'Ihe cushioning members preferably are secured to the overload springitself by suitable means such asthe holders 53 shown in the drawing. Each of the holders, as shown, consists of a lower horizontalportion 54 which is engaged by the bolt 44 to retain the holder in place. The horizontal portion 54 is provided with downwardly extending anges 56 which engage the side edges of the leaf 26 and serve to prevent lateral movement of the holder. The holder is also provided with a pir of upwardly and inwardly turned lips 57 which engage the base portion 51a of the cushioning member 51 to firmly hold the cushioning member 51 in place.

Mounting and operation of my overload spring may now be described as follows: In mounting the overload spring, the weight is lifted from at least one rear wheel of the vehicle by suitable means such as a bumper jack until the semi-elliptical spring associated therewith is in a substantially unloaded condition. In this condition, as is well known, the arch of the semi-elliptical spring is greater than when it is loaded by weight of the vehicle. The overload spring 11 is then grasped and aligned with the semi-elliptical spring so that it immediately underlies the semi-elliptical spring. The two upper parts 31 which may be called hooks of the clamps 27 and 28 are faced in opposite directions and then hooked over the semi# elliptical spring on vopposite sides of the portion of the semi-elliptical spring to which the axle housing 17 is secured.

The lower extremities of the upper portions 31 arel held in an outward position away from the semiellipticalA leaf spring as shown in Figure 4 during the hooking operation and then moved inwardly to engage the lower parts 32 to cause the tongues 36 to pass through the openings 34. The outwardly inclined portions 31e of the upper parts 31 permit the necessary tilting of the upper parts 31 for this operation as shown particularly in Figure 4.

After both of the clamps 27 and 28A are in place, the brackets 41 and 42 are secured to the'semi-ellip'ltical spring by inserting the keeper"1 bolts 47 through the spacers 49 and tightening the nuts 48. As soon as this has been accomplished, the bumper jack may be removed to allow the weight of the vehicle to again rest upon the semielliptical spring. Since the overloadA spring 11 has an arch which is substantiallygreater than the arch of the loaded semi-elliptical spring 12, it is apparent that as the weight of the vehicle is lowered onto the semi-elliptical spring 12, the cushioning members 5,1 will come into engagement with the ends' .of the semi-'elliptical spring and will causestress to be applied to the clamps 27 and 28. This stressing of the clamps 27 and 28 and the overload spring serves to lock the clamps in position.

In operation, it is apparent that the overload spring 11 will act as a helper spring and will supplement the.4

action of the semi-elliptical spring 12. The brackets 27 and 28 limit the maximum spacing between the overload spring 11 and the semi-elliptical spring 12. The continuous forces applied to the clamps by the spring prevents accidental disengagement of the clamps. In addition, the downwardly turned tongues 36 also serve to prevent accidental disengagement of the upper portions 31 of the clamps fromthe lower portions- 32.v The'downwardly .turned portions 31p' of the upper part 3l is of suiiicient length that it 'is impossible' for the upper part to become accidentally unfastened from the semi-elliptical spring, such-asfor elxample, when the vehicle passes over bumps and the like..

As hereinbefore explained, the clamps 27 and 28 are mounted on the semi-elliptical springin' auch am'anner '4 that they face in opposite directions. The primary purpose for such mounting is to equalize the loading on the semi-elliptical spring and to prevent tipping or tilting of the overload spring with vrespect to the semi-elliptical spring.

The cushioning members 51 serve to insure noise-free action of the overload spring because they prevent the ends of the overload spring from coming in direct contact with the semi-elliptical spring. In this manner, scraping or rattling noises are prevented. The brackets 41 with the keeper bolts merely serve as guide means for the outer ends of the semi-elliptical spring and insure that the overload spring will always remain in alignment with the semi-elliptical spring. In addition, the brackets 41 provide additional insurance that the overload spring cannot accidentally become unfastened from the semielliptical spring.

It will be noted that the overload spring is mounted very close to the bottom surface of the semi-elliptical spring 12 and therefore the clearance of the vehicle is not reduced substantially.

It is readily apparent that different types of clamps of the same type can be devised which will operate satisfactorily. For example, a tongue can be providedon the upper portion 31 which could extend through openings provided in the lower part 32 to form a suitable connection. e

Another embodiment of my invention is shown in Figure 5 in which the clamp is in one piece. This clamp 61 is substantially C-shaped as shown and is comprised of an outwardly extending portion 61a, a horizontal portion 61b, a vertical portion 61e, and an inwardly extending portion 61d. It is also comprised of a.- portion 61e and an outwardly turned portion 61f. The lower part of the clamp consisting of portions 61d, 61e, and 61f accommodate the leaves of the overload spring and are fastened thereto by suitable means such as the rivet 62. Separate means such as rivets or bolts can be provided (not shown) for securing they three leaves of the overload spring into a unitary assembly. The upper part of the clamp consisting of portions 61a, 61b and 61e is adapted to hook over the semiel1iptical spring 12 as shown in the drawing.

Since all portions of the clamp 61 are secured lto the leavesl of the overload spring, it is necessary to mount the overload spring in a manner dilerent from that described for the overload spring shown in Figuresul to 4. The clamps 61 are mounted on the overload spring in such a manner that they are spaced apa'rtnand facingin opposite directions. In mounting, the' vehicle is jacked up as hereinbefore described to increase 'the arch of the semi-elliptical spring. The overload spring is placed under the semi-elliptical spring so that one of the brackets is on one side of the semi-elliptical spring and the other bracket is on the other side of the semielliptical spring. The overload spring is then rotated slightly so that the semielliptical spring passes in to `the openings between portions 61a and 61! of the clamps and then the upper portion dropped over the semi-elliptical spring as shown in lFigure 5. The keeper bolts are theirl secured n a manner hereinbefore described and the jack is lowered to cause stressing of the overload spring ,11nd locking of the clamps in position as hereinbefore' de'- s cribed. It' will be noted in this embodiment, that'the clamp itself cannot be tilted and for that reason the portion 61a is not turned outwardly as are the portions slc on the slamp 21 and za.

It is apparent from the foregoing. that I have prn-V vided a new and improved overload spring whichm'y be quicklyattached to the vehicle and quickly vdetached when desired. The overload spring is securely .locked to the semi-elliptical spring and cannot become a'cc'g dentally unfastened. Since it can be readily 'attached and detached, it is particularly adaptablefor use'lls' sportsmen', campersl and the like who at certainV times wish to carry heavy loads or pull trailers with their vehicles.

I claim:

1. In an overload spring for use on a vehicle having a semi-elliptical spring with its opposite ends secured to the frame of the vehicle and an intermediate portion secured to the axle housing of the vehicle, the overload spring comprising at least one spring leaf adapted to underlie said semi-elliptical spring in alignment with said semi-elliptical spring, resilient cushioning means on the ends of the spring leaf and adapted to engage the semi-elliptical spring, and a pair of clamps mounted on said spring leaf and adapted to be secured to the semi-elliptical spring on opposite sides of the intermediate portion which is secured to the axle housing, each of said clamps having an opening on one side thereof facing in a direction at substantially right angles to the spring leaf the opening in one of said clamps facing in a vdirection opposite the'direction in which the opening in the other of said clamps is facing.

2. An overload spring as in claim 1 wherein each of said clamps is in two parts, one of said parts being fixed to the spring leaf and the other of said parts being detachably connected to said rst named part and engaging Said semi-elliptical spring, the engagement providing the sole connection with thc semi-elliptical spring.

3. In an overload spring for use on a vehicle having a semi-elliptical spring with its opposite ends secured to the frame of the vehicle and an intermediate portion secured to the axle housing of the vehicle, the overload spring comprising a leaf spring adapted to underlie said semi-elliptical spring in alignment with said semi-elliptical spring, resilient cushioning means secured to each end of the leaf spring and adapted to engage the bottom surface of the semi-elliptical spring, and a pair of clamps mounted on said leaf spring and facing in opposite directions, said clamps being adapted to engage said semi-elliptical spring on opposite sides of the intermediate portion secured to the axle housing, each of said clamps comprising an upper part adapted to hook over said semi-elliptical spring and a lower part secured to the leaf spring, said upper part being detachably connected to said lower part and being adapted to be swung into and out of engagement with the lower part.

4. An overload spring as in claim 3 wherein said upper part is in the form of a hook and wherein one portion of the upper part extends outwardly to permit tilting of the upper part with respect to the semi-elliptical spring.

5. In the combination of an overload spring and a semi-elliptical spring, the semi-elliptical spring being of a type used on a vehicle and having its opposite ends secured to the frame of the vehicle and an intermediate portion secured to the axle housing of the vehicle, the overload spring comprising a leaf spring underlying said semi-elliptical spring in alignment with said semi-elliptical spring, the leaf spring having an arch substantially greater than the arch of the semi-elliptical spring when loaded by the weight of the vehicle, a pair of clamps facing in opposite directions secured to said leaf spring anal hooked over the semi-elliptical spring on opposite sides of the portion of the semi-elliptical spring secured to the axle housing, said clamps serving to limit the spacingbetween the semi-elliptical spring and the leaf spring to place the leaf spring under stress to maintain the end portions of the leaf spring normally in engagement with the semi-elliptical spring, said clamps having openings in the sides thereof facing in opposite directions at substantially right angles to the leaf spring.

6. A combination as in claim 5 together with resilient cushioning means secured to the ends of the lent` spring and engaging the bottom surface of the semielliptical spring, and brackets secured to the ends of the leaf spring and loosely engaging said semi-elliptical spring near the ends thereof.

7. A combination as in claim 5 wherein said clamp consists of an upper part and a lower part, the upper part being in the form of a hook fitting over the semielliptical spring and a lower part xed to the leaf spring, a downwardly inclined tongue mounted on said lower part, the upper part being formed with an opening through which the tongue is adapted to extend.

8. In the combination of an overload spring and a semi-elliptical spring, the semi-elliptical spring being of a type used on a vehicle and having its opposite ends secured to the frame of the vehicle and an intermediate portion secured to the axle housing of the vehicle, the overload spring comprising a leaf spring underlying said semi-elliptical spring in alignment with said semi-elliptical spring, the leaf spring having an arch substantially greater than the arch of the semi-elliptical spring when loaded by the weight of the vehicle, a pair of clamps secured to the leaf spring and to the semi-elliptical spring, said clamps serving to limit the spacing between the semi-elliptical spring and the leaf spring to place the leaf spring under stress to maintain the end portions of the leaf spring normally in engagement with the semielliptical spring, said clamps having openings facing in opposite directions at right angles to the axis of the leaf spring so that the leaf spring can be mounted on the semi-elliptical spring by swinging the clamps into engagement with the semi-elliptical spring from opposite sides of the semi-elliptical spring when the arch of the semielliptical spring has been increased so that it is greater than the arch of the leaf spring.

9. In a combination as in claim 8 together with resilient cushioning means secured to the ends of the leaf spring and engaging the bottom surface of the semielliptical spring and brackets secured to the ends of the spring and loosely engaging said semi-elliptical spring near the ends thereof.

References Cited in the le of this patent UNITED STATES PATENTS 911,545 Senderling Feb. 2, 1909 1,709,487 Rauen et al Apr. 16, 1929 1,867,203 Blackmore et al July 12, 1932 2,112,148 Drolet Mar. 22, 1938 2,188,689 Marco Jan. 30, 1940 2,580,975 Tea Ian. 1, 1952 2,635,870 Laher Apr. 21, 1951 

